PostView: Also delegate `cache_version`
PostView: Also delegate `cache_version`

This may be needed as of https://github.com/rails/rails/commit/4f2ac80d4cdb01c4d3c1765637bed76cc91c1e35

Refs #839

thredded/thredded,thredded/thredded,thredded/thredded,thredded/thredded,jayroh/thredded,jayroh/thredded,jayroh/thredded,jayroh/thredded